Comparisons of the Molecular Forms of Activated Bovine Factor X

Abstract

Abstract Preparations of bovine Factor X zymogen were converted to enzymatically active forms with Russell's viper venom, with 25% sodium citrate, with a water-insoluble copoly-(maleic acid-ethylene)trypsin, with tissue factor (rabbit brain extract thromboplastin), and with a preparation designed to represent the intrinsic pathway of blood coagulation. The activated Factor X generated in each case was purified by chromatography on diethylaminoethylcellulose. Analytical ultracentrifugation, gel filtration, disc electrophoresis, sodium dodecyl sulfate-acrylamide electrophoresis, amino acid and carbohydrate analyses, carboxyl- and amino-terminal amino acid analyses, and peptide mapping of tryptic digests were used to show the striking molecular similarities of the enzymatically active products. Mixtures containing various combinations of the differently activated Factor X preparations behaved essentially as single species in disc electrophoresis, and after reduction with mercaptoethanol only two bands appeared in sodium dodecyl sulfate-acrylamide electrophoresis, as with each separate product. It was concluded that the diverse activation procedures yield essentially the same molecular form of activated Factor X.